NEET Electromagnetic Induction — Set 13

Question 1

A circular coil of radius 8 cm and 240 turns rotates at 45 rad/s in a 0.04 T field. What is the maximum emf induced?

Accepted Answer

$ A = \pi r^2 = 3.14 \times (0.08)^2 = 0.0201 \, \text{m}^2 $. $ \varepsilon_0 = N B A \omega = 240 \times 0.04 \times 0.0201 \times 45 = 8.676 \, \text{V} \approx 8.68 \, \text{V} $.

Question 2

A circular coil of radius 5 cm and 100 turns is rotated in a 0.1 T magnetic field at 50 rad/s. What is the maximum emf induced?

Accepted Answer

Maximum emf: $ \varepsilon_0 = N B A \omega $. $ A = \pi r^2 = 3.14 \times (0.05)^2 = 0.00785 \, \text{m}^2 $. $ \varepsilon_0 = 100 \times 0.1 \times 0.00785 \times 50 = 3.925 \, \text{V} \approx 3.93 \, \text{V} $.

Question 3

A solenoid with mutual inductance 0.22 H has a current change of 7 A/s in the primary coil. What is the induced emf in the secondary coil?

Accepted Answer

$ \varepsilon = M \frac{dI}{dt} = 0.22 \times 7 = 1.54 \, \text{V} $.

NEET Physics: Electromagnetic Induction — Practice Set 13

Q1. A circular coil of radius 8 cm and 240 turns rotates at 45 rad/s in a 0.04 T field. What is the maximum emf induced?

Q2. A circular coil of radius 5 cm and 100 turns is rotated in a 0.1 T magnetic field at 50 rad/s. What is the maximum emf induced?

Q3. A solenoid with mutual inductance 0.22 H has a current change of 7 A/s in the primary coil. What is the induced emf in the secondary coil?

Q4. In an AC generator, the maximum emf occurs when the coil is in which orientation relative to the magnetic field?

Q5. A solenoid of 600 turns per meter and area 0.012 m² has a current change from 4 A to 1 A in 0.2 s. What is the self-induced emf? (\( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \))

Q6. A rectangular loop of 0.3 m × 0.45 m moves out of a 0.5 T field at 0.9 m/s along its shorter side. What is the emf?

Q7. A magnet is moved away from a coil, and the induced current flows clockwise as viewed from the magnet. What is the polarity of the coil’s face towards the magnet?

Q8. A coil with \( L = 0.2 \, \text{H} \) has its current increased from 0 to 5 A in 0.5 s. What is the energy stored?

Q9. A coil of 140 turns and area 0.045 m² is in a field that decreases from 0.07 T to 0 in 0.35 s. What is the induced emf?

Q10. A circular coil of radius 4 cm and 250 turns rotates at 40 rad/s in a 0.06 T field. What is the maximum emf induced?